Flexible electrode support for electron discharge devices



R. WOOD FLEXIBLE ELECTRODE SUPPORT FOR ELECTRON DISCHARGE DEVICES FiledMarch 8, 1946 INVENTOR Ross W000 M June 29, 1948.

III/i/l/I/l Fla. 7

Patented June 29, 1948 I FLEXIBLE ELECTRODE SUPPORT FOR ELECTRONDISCHARGE DEVICES Ross Wood, Waltham, Mass, assignor to RaytheonManufacturing Company, Newton, Mass, a corporation of DelawareApplicationMarch 8, 1946, Serial No. 652,927

This invention relates to electron-discharge devices, and moreparticularly to the means by which filamentary cathodes are held intension within the device.

A large number of devices for supporting filaments in tension within anelectron-discharge device have been conceived but their use has beenconfined to electron-discharge devices of the well known conventionalsize. With the advent of sub-miniature electron-discharge devices suchas are used in hearing-aid apparatus, pocket-size radio receivers andother electronically-operated devices where extreme compactness is afirst requisite of construction, the importance of properly spacing andpositioning the minute elements within these sub-miniatureelectron-discharge devices poses a very difi'icult structural problem,namely, means for properly maintaining a directly heated filament inproper space relation to the control grid within the confines of anextremely small envelope having an internal diameter '04 the order of0.2 of an inch. Cantilever spring suspensions as ordinarily used in someminiature tubes, particularly those of a size somewhat larger than thepresent device, present many difiiculties when an attempt is made to usethem in the sub-miniature type tubes. Such a cantilever structure whenscaled down to meet the needs encompassed in a tube having a diameter asjust described would, by reason of its diminishing size, lose itselasticcharacteristic which is so essential to maintaining and supporting afilament in tension.

It is therefore an object of the present device to provide a filamentarysupport which will have a cantilever spring action in the longitudinalplane of an electron-discharge device in contradistinction to acantilever structure in the transverse plane as commonly used.

It is a further object to provide a support for a. filament which is aunitary structure capable of being deformed without acquiring a set inthe deformed position,

These and other objects will present themselves as the specificationprogresses and as evidenced by the attached drawing in which:

Fig. 1 is a cross-sectional view of one embodiment of the invention; and

Fig. 2 is a second embodiment, in cross section, of the presentinvention.

Referring now more particularly to Fig. 1, the drawing illustrates anevacuated envelope I containing therein electrode spacers II and I2,composed of mica for example, which serve to position the anodeelectrode I5 within the envelope I0.

8 Claims. (Cl. 250-275) The spacers I I and I2 are provided withapertures I1, 23, 24 and 25 through which are threaded the filamentarycathode I4 and the filament support I3. For the sake of clarity'theusual control grid has been omit-ted. However, the device can be used incombination with any number of electrodes.

The metallic support I3, which may be composed of tungsten for example,is rigidly aflixed, as by welding, to a metal tab 16 and extends onthrough the aperture I'I, said tab being in turn :fastened to the edgeof insulating spacer I2 by crimping thereto, or by any other suitablemeans. The free end of support I3 extends through aperture 23 in spacerI I and terminates in a short arm ISA. The filament I4 has tabs 2!] and2| amxed to each end thereof as by welding or other suitable means. Thetalb 20 is welded to the end of the short arm I3A of the support and thetab EI welded to the cross bar I8 which in turn is zfastened, preferablyby welding, to the downwardly extending member I8A, said last-namedmember being riveted or otherwise firmly fastened to the spacer I2. Themanner of asseming the support I3 and filamentary cathode It will begiven in more detail hereinafter.

Electrically-conductive members I9 and ISA are firmly im beddcd withinthe press 22, said press being an integral part of the envelope Ill. Themembers I 9 and ISA serve to support the electrode assembly within theenvelope I0 and to conduct current to the respective electrodes. Lead-I9' is welded to the cross memlber I8, said cross member acting as asupport for one end of the filamentary cathode I4. Lead I9A is welded tothe lower end of support I3 which projects through aperture I1. Thisassembly pro vides a path for the conduction of current through the,filamentary cathode I4 when a potential is applied between the leads l9and ISA.

In the construction of the device, the length of the filament I I isfirst determined. Tabs 20 and 2! are then welded to the respective endsof said filament. Tab 20 is then welded, or otherwise :fastened to thespring arm I3A. Now ta-b 2| is dropped through the apertures 24, 25,spring arm I3A is depressed and tab 2I welded, to the cross member I8.This arrangement causes the support I3 to bow out or distort, and soprovide the necessary tension in filament I 4. Thus we have provided aunitary supporting structure, simple in its configuration, small in thatportion which must lie in the transverse position within the device, yetproviding a tension arrangement which is so resilient that it will nottake a set in the deformed position.

Fig. 2 illustrates a second embodiment of the present device in whichthe support is a flexible metal member 26, preferably composed oftungsten. This structure permits even greater latitude in reducing. thesize of. the envelope l0. Its advantages will' be taken up asthisyspeciflcation progresses. In this particular embodiment, the tab 2!is fastened, by welding or otherwise, directly to the member I8A.

In Fig. 2, the short arm I3A is dispensed with to enable theconstruction of devices of the type described having stillsmaller'internal diameters. Here the construction of the support -26'isin the nature of a half-portion of a string and bow arrangement, the tabl6 being the pointof fulcrum. In this particular embodiment'theconstruction is simplified further by threading :the filament I4 throughthe apertures 24 and 25 and fastening the tab zl directly tot-he memberISA, thusobviating theextended member l8. As can be readily observed thetension in the filament is similar to the tension in the string of a bowwhich has been pulled taut.

Although several embodiments of, this invention have been described andillustrated, it is of course understood that many -,modifications andalterations may be made wherein the relation of the electrodes maybealtered to achieve the primary conception of thisinvention; for example,a plurality of filament supports may be placed diametrically, oppositeeach other for the purpose of constructing a dual diode or triode havingseparate filaments within the small space as.

hereinbefore described, or such supports may be readily used in tubes oflarger diameter with equal effectiveness.

What claimed is:

1. An electrode support comprising a flexible member of unitaryconstruction, a major portion of the length of said member beingsubstantially parallel with an electrode attached thereto, means forrigidly supporting one end of said .member, means for fastening saidelectrode to the unsupported end ofsaid flexible member, and

-means for rigidly supporting the opposite end of .said electrode tocause said flexible member to distort under-tension.

2. An electrode support comprising a flexible L-shaped member, means forrigidly fastening one end of an, electrode to one arm of said member,means for rigidly supporting the other arm of said member, and meansforrigidly fastening the opposite end of said electrode to cause saidmember to distort under tension.

3. An electrode support. comprising a flexible -S a-ped member havingarms of substantially differing lengths, means for rigidly fastening oneend of an electrode to the shorter arm of said member, means for rigidlysupporting the end of the longer arm of said member, and means forrigidly fastening the opposite end of said electrode to cause saidmember 'to distort under tension.

4. An electrode support comprising a flexible unitary L-shaped memberhaving arms of substantially differing lengths, the longer arm of saidmemberbeing substantially parallel with an electrode attached to the endof the shorter arm,

4 thereof, means for rigidly fastening one end of said electrode to theend of the shorter aim of said member, means for rigidly supporting theend of the longer arm of said member, and means for rigidly fasteningthe opposite end of said electrode to cause said member to form a bowunder the tension. c

, 5. In an electron discharge device, the combination of an envelopecontaining an electrode assembly, insulating spacers having aperturestherein for the passage therethrough of said electrodes, at least one ofsaid spacers having a metal tab attached to the edge thereof, a secondmetal tab attached to said first-named spacer, said second-named tabbeing disposed between said firstnamed tab and an, aperture in thecenter of said spacer, an electrode support comprising a flexible metalmember, a major portion of the length of said member being substantiallyparallel with an electrode attached to one end thereof, the opposite endof said member being rigidly affixed to said first-named tab, andtheother end of. said electrode being attached ,to said second-named tab tocause said support to distort under tension.

6.. In an electron discharge device, the combination of an envelopecontaining electrode spacing means, at least one of said spacing meanshaving means for rigidly attaching thereto at least one electrode, saidspacing means .having apertures therein for the passage therethrough of,said electrode, an electrode support comprising a flexible unitary,member, a major portion of the length of said support beingsubstantially parallel with an electrode attached thereto, said supportbeing rigidly attached to a first of said spacing means, the free end ofsaid support extending through an aperture in a second of said spacingmeans, and means for attaching said electrode to the free end of saidsupport, the opposite end of said electrode being firmly afiixed to saidfirst-named spacing means to cause said support to distort undertension.

.7. An electrode support comprising a unitary member having arms ofsubstantially difiering lengths, the shorter of said arms beingrelatively rigid with respect tothe longer of said arms, means "forattaching one end of. anelectrode to the shorter arm of said member,andmeans for one end ofqan electrode to the shorter arm of said member,and means for attaching the opposite end ,of said electrode to causesaid longer arm to distort under the tension.

ROSS WOOD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,042,554 Round June 2, 19362,266,080 Rockwood Dec. 16, 1941

